Porous Bi Nanosheets Derived from ß-Bi2O3 for Efficient Electrocatalytic CO2 Reduction to Formate.

The electrochemical CO2 reduction reaction (ECO2RR) is a promising strategy for converting CO2 into high-value chemical products. However, the synthesis of effective and stable electrocatalysts capable of transforming CO2 into a specified product remains a huge challenge. Herein, we report a template-regulated strategy for the preparation of a Bi2O3-derived nanosheet catalyst with abundant porosity to achieve the expectantly efficient CO2-to-formate conversion. The resultant porous bismuth nanosheet (p-Bi) not only exhibited marked Faradaic efficiency of formate (FEformate), beyond 91% in a broad potential range from -0.75 to -1.1 V in the H-type cell, but also demonstrated an appreciable FEformate of 94% at a high current density of 262 mA cm-2 in the commercially important gas diffusion cell. State-of-the-art X-ray absorption near edge structure spectroscopy (XANES) and theoretical calculation unraveled the distinct formate production performance of the p-Bi catalyst, which was cocontributed by its smaller size, plentiful porous structure, and stronger Bi-O bond, thus accelerating the absorption of CO2 and promoting the subsequent formation of intermediates. This work provides an avenue to fabricate bismuth-based catalysts with high planar and porous morphologies for a broad portfolio of applications.

Chemical reduction-induced defect-rich bismuth oxide-reduced graphene oxide anode for high-performance supercapacitors.

We prepare bismuth oxide-reduced graphene oxide (Bi2O3-rGO) composite anode using a one-step chemical precipitation/reduction method. Under a reducing atmosphere, oxygen atoms on the surface of Bi2O3 are gradually removed and neighboring oxygen atoms migrate to the surface, leaving oxygen vacancies. Defective Bi2O3 enhances the number of active sites, providing additional pseudocapacitive performance. The transition metal oxide-based Bi2O3 acts as an anode, providing capacitive performance that far exceeds that of conventional carbon materials. Moreover, the introduction of rGO forms a conductive network for Bi2O3, improving capacitive contribution and ion diffusion capabilities for the electrode. The Bi2O3-rGO-100 (GO added at 100 mg) exhibits a high specific capacitance of 1053F/g at 1 A/g, significantly higher than that of Bi2O3 (866F/g). The Bi2O3-rGO-100 anode and Ni3Co2-rGO cathode are assembled into a battery-type supercapacitor. The coin-cell device achieves an energy density of 88.2 Wh kg-1 at a power density of 850 W kg-1. The Ni3Co2-rGO//Bi2O3-rGO-100 pouch-cell device demonstrates an extremely low Rct of 0.77 Ω. At a power density of 850 W kg-1, the energy density reaches 118.5 Wh kg-1, and remains 67.4 Wh kg-1 at 8500 W kg-1.

Bismuth drug-inspired ultra-small dextran coated bismuth oxide nanoparticles for targeted computed tomography imaging of inflammatory bowel disease.

Bismuth (Bi)-based computed tomography (CT) imaging contrast agents (CAs) hold significant promise for diagnosing gastrointestinal diseases due to their cost-effectiveness, heightened sensitivity, and commendable biocompatibility. Nevertheless, substantial challenges persist in achieving an easy synthesis process, remarkable water solubility, and effective targeting ability for the potential clinical transformation of Bi-based CAs. Herein, we show Bi drug-inspired ultra-small dextran coated bismuth oxide nanoparticles (Bi2O3-Dex NPs) for targeted CT imaging of inflammatory bowel disease (IBD). Bi2O3-Dex NPs are synthesized through a simple alkaline precipitation reaction using bismuth salts and dextran as the template. The Bi2O3-Dex NPs exhibit ultra-small size (3.4 nm), exceptional water solubility (over 200 mg mL-1), high Bi content (19.75 %), excellent biocompatibility and demonstrate higher X-ray attenuation capacity compared to clinical iohexol. Bi2O3-Dex NPs not only enable clear visualization of the GI tract outline and intestinal loop structures in CT imaging but also specifically target and accumulate at the inflammatory site in colitis mice after oral administration, facilitating a precise diagnosis and enabling targeted CT imaging of IBD. Our study introduces a novel and clinically promising strategy for synthesizing high-performance Bi2O3-Dex NPs for diagnosing gastrointestinal diseases.

Surface Area-Enhanced Cerium and Sulfur-Modified Hierarchical Bismuth Oxide Nanosheets for Electrochemical Carbon Dioxide Reduction to Formate.

Electrochemical carbon dioxide reduction reaction (ECO2RR) is a promising approach to synthesize fuels and value-added chemical feedstocks while reducing atmospheric CO2 levels. Here, high surface area cerium and sulfur-doped hierarchical bismuth oxide nanosheets (Ce@S-Bi2O3) are develpoed by a solvothermal method. The resulting Ce@S-Bi2O3 electrocatalyst shows a maximum formate Faradaic efficiency (FE) of 92.5% and a current density of 42.09 mA cm-2 at -1.16 V versus RHE using a traditional H-cell system. Furthermore, using a three-chamber gas diffusion electrode (GDE) reactor, a maximum formate FE of 85% is achieved in a wide range of applied potentials (-0.86 to -1.36 V vs RHE) using Ce@S-Bi2O3. The density functional theory (DFT) results show that doping of Ce and S in Bi2O3 enhances formate production by weakening the OH* and H* species. Moreover, DFT calculations reveal that *OCHO is a dominant pathway on Ce@S-Bi2O3 that leads to efficient formate production. This study opens up new avenues for designing metal and element-doped electrocatalysts to improve the catalytic activity and selectivity for ECO2RR.

Novel defect-transit dual Z-scheme heterojunction: Sulfur-doped carbon nitride nanotubes loaded with bismuth oxide and bismuth sulfide for efficient photocatalytic amine oxidation.

The rational design of Z-scheme heterojunction hybrid photocatalysts is considered a promising way to achieve high photocatalytic activity. In this study, a dual Z-scheme heterojunction with bismuth sulfide (Bi2S3) nanorods and bismuth oxide (Bi2O3) nanoparticles anchored Sulfur-doped carbon nitride (S-CN) nanotubes (Bi2S3/S-CN/Bi2O3) is designed and fabricated through the ordinal metal ion adsorption, pyrolysis, and sulfidation processes using supramolecular rods as precursor. Compared with pristine Bi2S3, Bi2O3, and CN, the dual Z-scheme tube-shaped Bi2S3/S-CN/Bi2O3 catalyst exhibited a significantly improved photocatalytic activity in amine oxidation. The optimized Bi2S3/S-CN/Bi2O3 nanostructure exhibits a 97.6 % benzylamine conversion and 99.4 % imine selectivity within 4 h under simulated solar light irradiation. The excellent activity of Bi2S3/S-CN/Bi2O3 nanotubes can be attributed to the characteristic hollow defect band structure and efficient charge separation and transfer achieved by the dual Z-scheme charge transfer mechanism, which was systematically studied using electron spin resonance spectroscopy, Kelvin probe force microscope, and other techniques. The optimized dual Z-scheme heterojunction hybrid photocatalyst maintains the high oxidizing ability of Bi2S3 and Bi2O3 and the excellent reducing ability of CN, thereby significantly enhancing the photocatalytic activity. This research provides a facile and feasible synthesis strategy for designing dual Z-scheme heterojunctions with defect band structure to improve the photocatalytic activity.

Characterization of multifunctional ß-cyclodextrin-coated Bi2O3 nanoparticles conjugated with curcumin for CT imaging-guided synergetic chemo-radiotherapy in breast cancer.

Nanotechnology-based diagnostic, and therapeutic approaches revolutionized the field of cancer detection, and treatment, offering tremendous potential for cost-effective interventions in the early stages of disease. This research synthesized bismuth oxide (Bi2O3) nanoparticles (NPs) that were modified with polycyclodextrin (PCD), and functionalized with glucose (Glu) to load curcumin (CUR) for CT imaging and chemo-radiotherapy applications in Breast Cancer. The prepared Bi2O3@PCD-CUR-Glu NPs underwent comprehensive characterization, encompassing various aspects, including cell migration, cytotoxicity, cellular uptake, blood compatibility, reactive oxygen species (ROS) generation ability, real-time PCR analysis, in-vivo safety assessment, in-vivo anti-tumor efficacy, as well as in-vitro CT contrast and X-ray RT enhancement evaluation. CT scan was conducted before and after (1 and 3 h) intravenous injection of Bi2O3@PCD-CUR-Glu NPs. Through the use of coupled plasma optical emission spectrometry (ICP-OES) analysis, the final prepared nanoparticle distribution in the Bab/c mice was assessed. The spherical NPs that were ultimately synthesized and had a diameter of around 80 nm demonstrated exceptional toxicity towards the SKBr-3 breast cancer cell line. The cell viability was at its lowest level after 48 h of exposure to a radiation dose of 2 Gy at a concentration of 100 µg/mL. The combined treatment involving using Bi2O3@PCD-CUR-Glu NPs along with X-ray radiation showed a substantial increase in the generation of ROS, specifically a remarkable 420 % growth. Gene expression analysis indicated that the expression levels of P53, and BAX pro-apoptotic genes were significantly increased. The in-vitro CT imaging analysis conducted unequivocally demonstrated the notable superiority of NPs over Omnipaque in terms of X-ray absorption capacity, a staggering 1.52-fold increase at 80 kVp. The resultsdemonstrated that the targeted Bi2O3@PCD-CUR-Glu NPs could enhance the visibility of a small mice tumor that is detectable by computed tomography and made visible through X-ray attenuation. Results suggested that Bi2O3@PCD-CUR-Glu NPs, integrated with CT imaging and chemo-radiotherapy, have great potential as a versatile theranostic system for clinical application.

High-Performance Hard X-Ray Imaging Detector Using Facet-Dependent Bismuth Vanadate.

Bismuth vanadate (BiVO4) exhibits large absorption efficiency for hard X-rays, which endows it with a robust capacity to attenuate X-ray radiation across a broad energy range. The anisotropic properties of BiVO4 allow for the manipulation of their physical and chemical characteristics through crystallographic orientation and exposed facets. In this study, the issue of heavy recombination caused by sluggish electron transport in BiVO4 is successfully addressed by enhancing the abundance of the (040) crystal face ratio using a Co2+ crystal face exposure agent. The facet-dependent modifications exhibit excellent and balanced intrinsic charge transport properties, and finely optimize both the sensitivity and detection limit of BiVO4 X-ray detectors. As a result, ultra-stable BiVO4 metal oxide X-ray detectors demonstrate a high sensitivity of 3164 µC Gyair -1 cm-2 and a low detection limit of 20.76 nGyair s-1 under 110 kVp hard X-rays, establishing a new benchmark for X-ray detectors based on polycrystalline Bi-halides and metal oxides. These findings highlight the significance of crystal orientation in optimizing materials for X-ray detection, setting a new sensitivity record for X-ray detectors based on polycrystalline Bi-halides and metal oxides, which paves the way for the development of advanced, low-dose, and highly stable imaging systems specifically for hard X-rays.

Synthesis of folate targeted theranostic cubosomal platform for co-delivery of bismuth oxide and doxorubicin to melanoma in vitro and in vivo.

Liquid crystalline nanoparticles (LCNPs) have gained much attention in cancer nanomedicines due to their unique features such as high surface area, storage stability, and sustained-release profile. In the current study, a novel LCNP for co-encapsulation of Bi2O3 and hydrophilic doxorubicin (DOX) was fabricated and functionalized with folic acid (FA) to achieve efficient tumor targeting toward CT-scan imaging and chemotherapy of melanoma in vitro and in vivo. LCNPs Bi2O3 NPs were prepared using glycerol monooleate-pluronic F-127 (GMO/PF127/water). Firstly, GMO/water were homogenized to prepare LC gel. Then, the stabilizer aqueous solution (PF127/Bi2O3/DOX) was added to the prepared LC gel and homogenized using homogenization and ultrasonication. The formulated NPs exhibited superior stability with encapsulation efficiency. High cytotoxicity and cellular internalization of the FA-Bi2O3-DOX-NPs were observed in comparison with Bi2O3-DOX-NPs and the free DOX in folate-receptor (FR) overexpressing cells (B16F10) in vitro. Moreover, ideal tumor suppression with increased survival rate were observed in tumorized mice treated with FA-Bi2O3-DOX-NPs compared to those treated with non-targeted one. On the other hand, the CT-imaging ability of the Bi2O3-DOX-NPs was tested inB16F10 tumor-bearing mice. The obtained data indicated a high potential of the developed targeted theranostic FA-Bi2O3-DOX-NPs for diagnostics and treatment of melanoma.

Enhancement of the effect of novel targeted 5-aminolevulinic acid conjugated bismuth oxide nanoparticles-based photodynamic therapy by simultaneous radiotherapy on KB cells.

BACKGROUND: Selective accumulation of photosensitizers into cancerous cells is one of the most important factors affecting photodynamic therapy (PDT) efficacy. 5-aminolevulinic acid (5-ALA) is the precursor of a strong photosensitizer, protoporphyrin-IX; but it has poor permeability into the cells. Folate receptors are overexpressed on the surface of many tumor cells. In the present study, folic acid (FA) and 5-ALA conjugated bismuth oxide nanoparticles were synthesized; and used in PDT, radiotherapy (RT), and concurrent PDT & RT against nasopharyngeal carcinoma (KB cell line). METHODS: The KB cells were incubated with the synthesized nanoparticles (NPs) for 2 h; then illuminated using a custom-made LED lamp at the light dose of 26 J/cm2. Irradiation of the cells was carried out using X-ray 6 MV (2 Gy); and synergistic effect of the simultaneous RT and PDT treatments was evaluated using fractional product values. Efficacy of the treatments was determined using MTT and Caspase-3 enzyme activity assays. RESULTS: Targeting of folic acid receptors enables the selective endocytosis of the conjugated NPs. RT results in the presence of Bi2O3 NPs showed a significant radiosensitizer potential of these NPs. Fractional product values of 1.49±0.05, 1.36±0.06, and 1.05±0.06 obtained in the presence of FA-5-ALA conjugated NPs, 5-ALA conjugated NPs, and in the absence of the NPs, respectively. Therefore, simultaneous RT and PDT in the presence of these conjugated NPs is superior to RT in the presence of the NPs. CONCLUSION: Simultaneous PDT and RT in the presence of FA-5-ALA conjugated bismuth oxide NPs can be introduced as a promising therapeutic approach in controlling KB cancer cells.

The mechanism and reaction kinetics of visible light active bismuth oxide deposited on titanium vanadium oxide for aqueous diclofenac photocatalysis.

Non-uniform, non-spherical bismuth oxide deposited on titanium vanadium oxide (3%-BVT1) was successfully synthesized via co-precipitation method and assessed for visible light degradation of aqueous diclofenac. The synthesized photocatalysts were characterized using X-ray diffraction, diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. Up to 80.7% diclofenac degradation was observed with a significant increment in reaction rate compared to commercially available Degussa P25 (kapp = 0.0013 → 0.0083 min-1) achieved within 3 h treatment time under optimized parameters of diclofenac concentration (10 mg L-1), catalyst loading (0.1 g L-1), and pH (5). The enhanced photocatalysis could be due to electron-hole separation and contribution of powerful oxidative species •OH > O2•- > h+ > > e-. The recyclability experiments indicate that 3%-BVT1 retained its efficiency up to 74.1% over five reaction cycles. Gas chromatography-mass spectrometry analysis indicated the formation of several transformation products during the degradation pathway. The studies of interfering ions depicted mild interference by sulfates, while interference by phosphates and nitrates was negligible during photocatalytic process, i.e., 70, 78.01, and 78.43% for the selected concentrations of 50, 25, and 40 mg L-1 as per their maximum concentrations detected in the natural wastewaters. Thus, 3%-BVT1 is a potential versatile candidate to treat various organic pollutants including pharmaceuticals.

Fabrication and characterization of a Bi2O3-modified chitosan@ZIF-8 nanocomposite for enhanced drug loading-releasing efficacy.

In this study, a simple novel hybrid mesoporous nanomaterial derived from a metal-organic framework (ZIF-8) and chitosan, which were coated on green bismuth oxide, has been successfully synthesized, characterized, and applied to investigate its dapsone loading-releasing capability in the aqueous media. This suggested nanocomposite showed promise for drug loading from water b using hydrogen bonds, pi-pi, and electrostatic interactions. Structural and morphological analyses were performed on the proposed green synthesized nanocomposite through scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller analysis, and thermogravimetric analysis. Various influencing parameters, including pH, nanocomposite dose, and contact time, were investigated to optimize the dapsone loading process. Utilizing the non-linear optimization methodology, the results show that dapsone-loading efficiency was >85 % for 50 mg.L-1 of dapsone drug. The optimum parameters for achieving maximal loading of dapsone drug were pH = 6.8, hybrid mesosphere dose = 2.6 mg.mL-1, and time = 53 min. Based on the release investigations, the dapsone-loaded nanocomposite was put into phosphate buffer saline, at pH = 7.4 and T = 37 °C, with a maximum efficiency of 93.9 after 24 h.

Revealing the Intrinsic Restructuring of Bi2O3 Nanoparticles into Bi Nanosheets during Electrochemical CO2 Reduction.

Bismuth is a catalyst material that selectively produces formate during the electrochemical reduction of CO2. While different synthesis strategies have been employed to create electrocatalysts with better performance, the restructuring of bismuth precatalysts during the reaction has also been previously reported. The mechanism behind the change has, however, remained unclear. Here, we show that Bi2O3 nanoparticles supported on Vulcan carbon intrinsically transform into stellated nanosheet aggregates upon exposure to an electrolyte. Liquid cell transmission electron microscopy observations first revealed the gradual restructuring of the nanoparticles into nanosheets in the presence of 0.1 M KHCO3 without an applied potential. Our experiments also associated the restructuring with solubility of bismuth in the electrolyte. While the consequent agglomerates were stable under moderate negative potentials (-0.3 VRHE), they dissolved over time at larger negative potentials (-0.4 and -0.5 VRHE). Operando Raman spectra collected during the reaction showed that under an applied potential, the oxide particles reduced to metallic bismuth, thereby confirming the metal as the working phase for producing formate. These results inform us about the working morphology of these electrocatalysts and their formation and degradation mechanisms.

Functional Bi2O3/Gd2O3 Silica-Coated Structures for Improvement of Early Age and Radiation Shielding Performance of Cement Pastes.

This study presents a new approach towards the production of sol-gel silica-coated Bi2O3/Gd2O3 cement additives towards the improvement of early mechanical performance and radiation attenuation. Two types of silica coatings, which varied in synthesis method and morphology, were used to coat Bi2O3/Gd2O3 structures and evaluated as a cement filler in Portland cement pastes. Isothermal calorimetry studies and early strength evaluations confirmed that both proposed coating types can overcome retarded cement hydration process, attributed to Bi2O3 presence, resulting in improved one day compressive strength by 300% and 251% (depending on coating method) when compared to paste containing pristine Bi2O3 and Gd2O3 particles. Moreover, depending on the type of chosen coating type, various rheological performances of cement pastes can be achieved. Thanks to the proposed combination of materials, both gamma-rays and slow neutron attenuation in cement pastes can be simultaneously improved. The introduction of silica coating resulted in an increment of the gamma-ray and neutron shielding thanks to the increased probability of radiation interaction. Along with the positive early age effects of the synthesized structures, the 28 day mechanical performance of cement pastes was not suppressed, and was found to be comparable to that of the control specimen. As an outcome, silica-coated structures can be successfully used in radiation-shielding cement-based composites, e.g. with demanding early age performances.

Green synthesis of Ag and Cu-doped Bismuth oxide nanoparticles: Revealing synergistic antimicrobial and selective cytotoxic potentials for biomedical advancements.

BACKGROUND: Nanotechnology has emerged as a transformative realm of exploration across diverse scientific domains. A particular focus lies on metal oxide nanoparticles, which boast distinctive physicochemical attributes on the nanoscale. Of note, green synthesis has emerged as a promising avenue, leveraging plant extracts as both reduction and capping agents. This approach offers environmentally friendly and cost-effective avenues for generating monodispersed nanoparticles with precise morphologies. METHODS: In this investigation, we embarked on the synthesis of Bismuth oxide nanoparticles, both in their pure form and doped with silver (Ag) and copper (Cu). This synthesis harnessed the potential of Biebersteinia multifida extract as a versatile reducing agent. To comprehensively characterize the synthesized nanoparticles, a suite of analytical techniques was employed, including energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, and Raman spectroscopy. RESULTS: The synthesized nanoparticles underwent a rigorous assessment. Their antibacterial attributes were probed, revealing a pronounced enhancement in antibiofilm activity against Pseudomonas aeruginosa and Staphylococcus aureus bacteria upon metal nanoparticle doping. Furthermore, their potential for combating cancer was scrutinized, with the nanoparticles exhibiting selective cytotoxicity towards cancer cells, U87, compared to normal 3T3 cells. Notably, among the doped nanoparticles, Cu-doped variants demonstrated the highest potency, further underscoring their promising potential. CONCLUSION: In conclusion, the present study underscores the efficacy of green synthesized Bismuth oxide nanoparticles, particularly those doped with Ag and Cu, in augmenting antibacterial efficacy, bolstering biofilm inhibition, and manifesting selective cytotoxicity against cancer cells. These findings portend a promising trajectory for these nanoparticles in the spheres of biomedicine and therapeutics. As we look ahead, a deeper elucidation of their mechanistic underpinnings and in vivo investigations are essential to fully unlock their potential for forthcoming biomedical applications.

Synthesis, Characterization and Antimicrobial Activity of Multiple Morphologies of Gold/Platinum Doped Bismuth Oxide Nanostructures.

Bismuth oxides were synthesized from bismuth carbonate using the sol-gel method. Studies have described the formation of Bi2O3, as a precursor of HNO3 dissolution, and intermediate oxides, such as BixOy when using H2SO4 and H3PO4. The average size of the crystallite calculated from Scherrer's formula ranged from 9 to 19 nm, according to X-ray diffraction. The FTIR analysis showed the presence of specific Bi2O3 bands when using HNO3 and of crystalline phases of "bismuth oxide sulphate" when using H2SO4 and "bismuth phosphate" when using H3PO4. The TG curves showed major mass losses and specific thermal effects, delimited in four temperature zones for materials synthesized with HNO3 (with loss of mass between 24% and 50%) and H2SO4 (with loss of mass between 45% and 76%), and in three temperature zones for materials synthesized with H3PO4 (with loss of mass between 13% and 43%). Further, the thermal stability indicates that materials have been improved by the addition of a polymer or polymer and carbon. Confocal laser scanning microscopy showed decreased roughness in the series, [BixOy]N > [BixOy-6% PVA]N > [BixOy-C-6% PVA]N, and increased roughness for materials [BixOy]S, [BixOy-6% PVA]S, [BixOy-C-6% PVA]S, [BixOy]P, [BixOy-6% PVA]P and [BixOy-C-6% PVA]P. The morphological analysis (electronic scanning microscopy) of the synthesized materials showed a wide variety of forms: overlapping nanoplates ([BixOy]N or [BixOy]S), clusters of angular forms ([BixOy-6% PVA]N), pillars ([BixOy-6% PVA]S-Au), needle particles ([BixOy-Au], [BixOy-6% PVA]S-Au, [BixOy-C-6% PVA]S-Au), spherical particles ([BixOy-C-6% PVA]P-Pt), 2D plates ([BixOy]P-Pt) and 3D nanometric plates ([BixOy-C-6% PVA]S-Au). For materials obtained in the first synthesis stage, antimicrobial activity increased in the series [BixOy]N > [BixOy]S > [BixOy]P. For materials synthesized in the second synthesis stage, when polymer (polyvinyl alcohol, PVA) was added, maximum antimicrobial activity, regardless of the microbial species tested, was present in the material [BixOy-6% PVA]S. For the materials synthesized in the third stage, to which graphite and 6% PVA were added, the best antimicrobial activity was in the material [BixOy-C-6% PVA]P. Materials synthesized and doped with metal ions (gold or platinum) showed significant antimicrobial activity for the tested microbial species.

Photodegradation of CuBi2 O4 Films Evidenced by Fast Formation of Metallic Bi using Operando Surface-sensitive X-ray Scattering.

CuBi2 O4 has recently emerged as a promising photocathode for photo-electrochemical (PEC) water splitting. However, its fast degradation under operation currently poses a limit to its application. Here, we report a novel method to study operando the semiconductor-electrolyte interface during PEC operation by surface-sensitive high-energy X-ray scattering. We find that a fast decrease in the generated photocurrents correlates directly with the formation of a metallic Bi phase. We further show that the slower formation of metallic Cu, as well as the dissolution of the electrode in contact with the electrolyte, further affect the CuBi2 O4 activity and morphology. Our study provides a comprehensive picture of the degradation mechanisms affecting CuBi2 O4 electrodes under operation and poses the methodological basis to investigate the photocorrosion processes affecting a wide range of PEC materials.

Influence of the addition of different metal oxides on physicochemical and biological properties of calcium fluorosilicate/PCL bone cement.

Calcium silicate cements have been greatly developed in the last decades through different approaches. Among these approaches, the inclusion of antibacterial agents or addition of metal oxides. Herein, calcium silicate cement containing fluorine (CFS) was developed from sodium fluorosilicate precursor for the first time using chemical perception method. Afterwards, metal oxide Bi2O3 or MgO or ZrO2 was individually mixed with CFS powder and blended together using Polycaprolactone polymer (PCL). The cement mixtures were characterized using DSC, XRD, FTIR and SEM/EDX to determine the effect of metal oxide on the pure CFS. Furthermore, mechanical, antibacterial and cell viability properties were evaluated for the developed CFS mixture cements. Moreover, these CFS mixture cements were implanted in male Wistar rats to determine the effect of metal oxides on the rate of bone reformation. The findings of physicochemical and morphological characterization showed no remarkable effects on the pure CFS after mixing with each metal oxide. However, enhanced compressive strengths (up to 104.07N/cm2), antibacterial activity and cell viability (up to 96%) were achieved for the CFS cement mixtures. Finally, the in vivo studies confirmed the biocompatibility of the CFS cement mixtures and especially those mixed with Bi2O3 or ZrO2. Therefore, this study supports that CFS blends with Bi2O3 or ZrO2 can be novel promising cementing materials for bone restoration.

Bismuth Oxide Composite-Based Agricultural Waste for Wound Dressing Applications.

The purpose of this study was to enhance the antimicrobial activity of bagasse paper by coating the paper with bismuth oxide (Bi2O3) and using it to accelerate the process of wound healing. Paper sheets were prepared from sugarcane waste (bagasse). First, the paper sheets were coated with different Bi2O3 concentrations to improve the antimicrobial activity of the paper. After that, the paper sheets were allowed to dry in an oven at 50 °C for 3 h. Then, in vitro antimicrobial activity was evaluated against different microbial species, including Gram-negative bacteria (i.e., Klebsiella pneumonia, Escherichia coli) and Gram-positive bacteria (i.e., Staphylococcus aureus, Streptococcus pyogenes). The obtained results showed that the paper coated with 25% and 100% Bi2O3 had activity against all models of bacteria; however, the paper coated with 100% Bi2O3 composite had the strongest inhibitory effect. Then, bagasse paper was coated with 100% Bi2O3 and different antibiotics, to investigate their wound-healing potency in a wounded rat model for 14 days. Moreover, the paper coated with 100% Bi2O3 inhibited the cellular migration in vitro. Conclusively, coating paper with Bi2O3 enhances the wound-healing potential when applied to wounds. This impact could be ascribed to Bi2O3's broad antibacterial activity, which reduced infection and accelerated the healing process.

Preparation of Bi2O3-YSZ and YSB-YSZ Composite Powders by a Microemulsion Method and Their Performance as Electrolytes in a Solid Oxide Fuel Cell.

Bi2O3 is a promising sintering additive for YSZ that not only decreases its sintering temperature but also increases its ionic conductivity. However, Bi2O3 preferably grows into large-sized rods. Moreover, the addition of Bi2O3 induces phase instability of YSZ and the precipitation of monoclinic ZrO2, which is unfavorable for the electrical property. In order to precisely control the morphology and size of Bi2O3, a microemulsion method was introduced. Spherical Bi2O3 nanoparticles were obtained from the formation of microemulsion bubbles at the water-oil interface due to the interaction between the two surfactants. Nanosized Bi2O3-YSZ composite powders with good mixing uniformity dramatically decreased the sintering temperature of YSZ to 1000 °C. Y2O3-stabilized Bi2O3 (YSB)-YSZ composite powders were also fabricated, which did not affect the phase of YSZ but decreased its sintering temperature. Meanwhile, the oxygen vacancy concentration further increased to 64.9% of the total oxygen with the addition of 5 mol% YSB. In addition, its ionic conductivity reached 0.027 S·cm-1 at 800 °C, one order of magnitude higher than that of YSZ. This work provides a new strategy to simultaneously decrease the sintering temperature, stabilize the phase and increase the conductivity of YSZ electrolytes.

Co+2, Ni+2 and Cu+2 incorporated Bi2O3 nano photocatalysts: Synthesis, DFT analysis of band gap modification, adsorption and photodegradation analysis of rhodamine B and Triclopyr.

This study deals with the fabrication of metal ion (M = Co+2, Ni+2, and Cu+2) doped- Bi2O3 photocatalysts by solution combustion method. All the synthesized materials were characterized and analysed with the help of XRD, FESEM, EDX, HRTEM, UVDRS, Zeta potential, PL, and LCMS techniques for the structural, morphological, surface charge, optical and degradation pathways characteristics. Synthesized compounds were used for the decontamination (adsorption and degradation) of two organic pollutants namely Rhodamine B and Triclopyr. Adsorption aspects of the pollutants were studied in terms of different isotherm, kinetic and thermodynamic models. Adsorption phenomenon was best fitted with the Freundlich (R2 = 0.992) and Langmuir isotherm (R2 = 0.999) models along with pseudo second order model of kinetics for RhB and TC, respectively. Moreover, the thermodynamic parameters indicated exothermic and endothermic adsorption (ΔH ° (-7.19 kJ/mol) for RhB) and (ΔH ° (52.335 kJ/mol) for TC), respectively. Evaluated negative values of ΔG ° indicated spontaneous adsorption with most favourable at 298 K and 318 K for both the pollutants (RhB and TC) respectively. Modification with metal ions significantly improved the removal efficiency of pure Bi2O3 photocatalyst and followed the trend Co+2/Bi2O3 > Ni+2/Bi2O3 > Cu+2/Bi2O3 > Bi2O3. DFT calculations demonstrate that amongst the doped materials, only Co+2/Bi2O3 is characterized by an indirect band gap; which exhibited efficacious photocatalytic activity. Besides, the highest degradation efficiency was obtained in the case of Co+2/Bi2O3 (2 mol %); being 99.80% for RhB in 30 min and 98.50% for TC in 60 min, respectively. The doped nanostructures lead to higher absorption of visible light and more separation of light-induced charged carriers. Effect of pH of the reaction medium and role of reactive oxygen species was also examined. Finally, a probable mechanism of charge transfer and degradation of the pollutants was also presented.